The present invention relates to electrical switchgear and, more particularly, to a mechanism operated cell (MOC) switch operator for a vacuum operated circuit breaker.
A well known limitation of roll-in-replacement (RiR) circuit breakers, which replace legacy air magnetic circuit breakers, is that the mechanism travel of the vacuum breaker is much shorter and the velocity (relative to the distance travel) is much higher than the breakers which they are replacing. Additionally, the excess energy available for driving these panel mounted external switches is less in the more modern circuit breakers.
A mechanism-operated cell (MOC) switch is typically located in a switchgear cell and is operated by a circuit breaker MOC operator mechanism. A typical example may be found in U.S. Pat. No. 4,176,262, the content of which is hereby incorporated by reference into this specification. The MOC switch is employed to provide extra or redundant contacts for circuit breaker status and status control.
When applying modern technology circuit breaker elements, as retrofit or replacement RiR circuit breakers, for the older technology circuit breakers, worn MOC assemblies may possibly create problems. For example, the velocity of the new mechanism is much faster; the travel motion of the driver must be multiplied in driving the panel mounted component; the available energy in the circuit breaker is lower; and because in a retrofit situation, the panel equipment is typically 30 or more years of age so an optimal configuration must allow for age and potentially poor maintenance of the installed equipment resulting in increased friction and reduced tolerance for sudden accelerations.
Thus, there is a need to provide an improved MOC operator structure for a switchgear assembly that slows down motion of the mechanism and ensures that energy of operating the MOC does not interfere with the basic circuit breaker closing.